1. Field of the Invention
The present invention relates to an image processing apparatus on which an image forming engine for forming a full-color image on a recording medium by using color materials corresponding to color data on the basis of C, M, Y, K data is mounted.
2. Description of the Related Art
It is known to provide an image forming apparatus that receives RGB data output from a host computer or the like, converts the RGB data to CMYK data, records an electrostatic latent image onto a photosensitive member in correspondence with the color data, develops the image by using toners of the colors, and transfers the image onto a recording medium (recording paper), thereby obtains a full-color image.
In the case of generating CMYK data from RGB data, first, CMYK data is generated from RGB data. Next, when amounts of C, M, and Y are equal to each other, the equal amounts are replaced with K data. The K data amount is set as a base and subtracted from the original C, M, and Y data, thereby generating each of the C, M, and Y data.
As a conventional method of generating K data, the difference between the maximum and minimum values of CMY data is regarded as saturation information. When amounts of C, M, and Y data are equal to each other, it is determined that saturation is low, and K data is generated so as to be maximum.
In such a K data generating method, however, there is a case such that K data becomes the maximum in a color having rather low saturation. As a result, excellent color reproduction is not achieved, and a problem occurs such that tone reproducibility deteriorates and spreading occurs in a low saturation part in which the K data is generated maximally.